1. Field
This invention relates generally to orthopedic devices for assisting in patient exercise and more specifically to an inflatable oscillating pillow for moving body extremities which a patient would otherwise be unable to move.
2. Prior art
Incapacitation of body parts is among the results of any number of maladies, for example diseases of the central nervous system. Cerebrovascular ailments, cerebral injury, cerebral palsy, spinal cord damage, as well as disfunctions of the peripheral nervous system, joints, muscles and tendons are only a few of the causes of incapacitation of body parts.
A great many devices and apparatus are known whereby extremity functions lost to such disease or injury may be partially or completely regained. In particular, devices are known in which a pillow or similar inflatable bag is disposed below the body part and oscillated by mechanical driving means to cause the incapacitated body part to move. These devices have been found to be somewhat effective because gentle passive stretch of incapacitated muscles reduces resistance to increased stretch and also quiets abnormal reflex activity.
For example, U.S. Pat. No. 4,671,258, issued to Barthlome, discloses a device which utilizes a spring to bias the inflatable pillow in a retracted condition, with the pillow responding upon inflation to extend. U.S. Pat. No. 4,003,374, issued to Mizrachy, utilizes a bellows-type drive system which is powered by a fluid source. A rigid plate is also included in the '374 patent, which represents an older concept in exercise devices. Such a rigid plate has the distinct disadvantage of being incapable of conforming to the body part to be moved. U.S. Pat. No. 3,492,988, issued to DeMare, has the same disadvantage as the '374 patent.
U.S. Pat. No. 4,619,250, issued to Hasegawa, and U.S. Pat. No. 4,596,240, issued to Takahashi, are adapted specifically for hand therapy and include mechanical drive means. In particular, the '240 patent requires the use of a mechanical valve to cycle the inflation/deflation of the pillow. Similarly, the '250 patent provides for a complex mechanical drive system which can easily break, is inordinately expensive, and is difficult to repair.
Furthermore, none of the prior art includes an oscillating pillow wherein the oscillation cycles are responsive to the patient's movements. Rather, each prior art patent discloses an oscillating mechanism which is time controlled, i.e. each inflation and deflation of the cycle is set to a specified time. Such an arrangement has the undesired effect of forcing the limb to be exercised to move in a certain manner. This may prove harmful to the patient when experiencing spasms caused by cerebral or muscular disorders or even coughing. An oscillating pillow system, therefore, would advantageously be provided with a switch or similar mechanism which regulates the oscillations according to pressure variations within the system, such as those caused by a patient's spasms, rather than by time actuated means.
Therefore, there exists in the art a legitimate need for a system which provides an oscillating pillow wherein the oscillations are provided by a pressure sensitive simplified, inexpensive, easily manufactured valve or switch. Further, there exists a need for an oscillating pillow which is specifically designed to accommodate each individual body part.